Why are there different amplitude lines?

Random images in Lightburn show wavy lines in whitespace. This was pre-dithered with GIMP and the newsprint dither can be seen in the black areas. The white and gray areas have waves of different amplitudes, and you can see them overlapping actually if you look closer. You can see white paths cutting through the larger amplitude waves, which lead me to think it’s some kind of rendering problem? Pass through was selected, 363 DPI, 42% power @ 6000 mm/min on a Ortur 20W diode laser master 2. Any idea on how to avoid this wave artifact? I don’t think it’s only the moire artifacts at play here. It particularly tends to show up when I process images in lightburn with Greyscale.

here’s the processed file